Allaah, the Blessed and High, says:
“He (Allaah) has ordained for you the same religion which He ordained for Nooh (Noah), and that which We have inspired in you (O Muhammad0), and that which We ordained for Ibraheem (Abraham), Moosaa (Moses?) and ‘Eesaa (Jesus) saying you should establish religion and make no divisions in it.”
[Soorah Ash-Shura 42:13]
This is the command of Allaah, the Blessed and High, and His Legislation for His Prophets and the Messengers of Strong Will; establishment of the religion and not dividing in it. This verse contains the most beneficial solution and the safest remedy to quell the differing and to set in order the disarray.
Establishment of the religion is by way of clinging to their religion which Allaah, the Blessed and High, has commanded them with, and preserving it. There is no solution other than this and there is no remedy except it. In establishing the religion, there lies cutting off of the splitting which the people fall into. This is by way of completely returning to the religion.